I went to public school in a blue state and it was not far left. The labor movement was taught as a handful of very bad situations that caused workers to strike and peaceful protest fixed it. Things like the Battle of Blair Mountain and the violence it took to get where we are were ignored. Same with civil rights, MLK Jr gave some speeches, some people marched, there was resistance, and then we fixed it.
Any non capitalist leanings were ignored or minimized, the organized violence of the state and those who opposed it was ignored, figures were lauded and their life summaries always left out the part were they criticized capitalism or the complacent middle class. No mention of Mother Jones, Smedly Butler, our involvement in Iran as a pre shah state, or anything that would tarnish America’s image as a modern moral state. Hell, they never had the nerve to call what we did to the Native Americans a genocide.